It's down to business at the Women's World Cup as the knockout rounds get under way Saturday with top-ranked Germany and former runners-up China both in action.

Germany, winners in 2003 and 2007, take on Sweden in the opening last 16 clash in Ottawa with China next up against ambitious African newcomers Cameroon in Edmonton.

Previous results are all forgotten now, including Germany's 10-0 hammering of Ivory Coast, or Sweden's struggles to advance, in a one-off free for all.

"What has happened before doesn't really matter now because this is where it really starts," said Germany coach Silvia Neid.

"You won't be given 10 opportunities, you have to seize the two or three you get. You have to concentrate and be cool in the last 16 or go home."

Reigning champions Japan kept their defense on track by winning all three of their group matches with only Brazil, the 2007 runners-up, posting a better record, as both took maximum points.

Brazil face a tougher test in the last 16 clash against Australia in Moncton on Sunday than in their group games against South Korea, Costa Rica and Spain.

Japan also face a tricky tie against a young Dutch side, who advanced as third in their Group A, in Vancouver on Tuesday.

The United States, two-time winners, counted on veterans Megan Rapinoe, Abby Wambach and Hope Solo to keep them on track with two wins and a draw against Sweden and next clash with Colombia, who shocked France 2-0 in their second group game, next in their sights in Edmonton on Monday.

France, ranked third, finished top of their group ahead of England and next play South Korea, who got past the group stage for the first time, on Sunday in Montreal. England set up a clash with former champions Norway on Monday.

Hosts Canada qualified top of their Group A and continue their bid for a first title against Switzerland in Vancouver on Sunday.

"The games only get tougher now," said Canada coach John Herdman.

Germany topped Group B with two wins and a draw, as the fifth-ranked Swedes backed into the last 16 as one of the best four third-placed finishers following three draws.

European champions Germany have demonstrated an impressive forward line with 15 goals in three games including four from Anja Mittag and three from Celia Sasic.

Sweden, runners-up in 2003 and third in 2011, emerged batter and bruised from Group D, the so-called 'Group of Death', where the United States took top spot ahead of Australia.

Coach Pia Sundhage was deflated after her side managed just three points from three draws.

"We didn't lose (in the group), and we scored four goals but we didn't do enough to win the group or even be runnersup," said 55-year-old Sundhage, who coached the US to two Olympic golds and silver at the last World Cup.

But Australia coach Alen Stajcic believes all of the 'Group of death' survivors are now contenders.

"These three teams have been battle hardened, it just toughens you up for the biggest matches where any slipup and you're out," he said.

"Whoever gets out of our group can make the semi-finals as a minimum," Stajcic predicted.

And Neid is not taking the demoralized Swedes lightly.

"Sweden have a lot of quality on their team. The games we have played against them have always been competitive and close-fought," she said.

"As of now, we have to show passion and give everything. The team in better form on the day will go through to the quarter-finals."

China's young side, who finished second in Group A behind Canada, face a challenge from debutants Cameroon, just the second African nation to reach the knockout rounds.

Chinese coach Hao Wei was banished from the sideline as tempers flared during their crucial final game against New Zealand.

Hao has overseen the blossoming of the 'Steel Roses' who were a footballing power in the 1990s, and are now ranked 16th.

But Cameroon, ranked 53, have also proved they have their place among the big girls.

They opened with a 6-0 whipping of Ecuador, took on champions Japan in a hard-fought 2-1 loss, before seeing off Switzerland 2-1.

"The Chinese are a great team, they are very fast, with a Japanese-style football," said Cameroon coach Enow Ngachu.

"We know it will be very tough, but we have shown that we learning and if we can surprise China even better."